This paper describes the exploratory part of a larger study on management of innovation, focussing especially on the interface between marketing and R&D (Research and Development). Marketing and R&D produce two critical flows of knowledge that have to be integrated in the interface. In this study we focus on one specific industry, namely the innovative pharmaceutical industry because of its high marketing and R&D intensity. Our conceptual model is based on the literature and on exploratory case studies of four pharmaceutical companies where variables are identified that seem important. With respect to the marketing - R&D interface, the qualitative data from in-depth interviews, company library research and financial analysis of the four companies support three main arguments. First, organizational structures change very often which implies that organizational flexibility (adaptability of the company) may be an important aspect in explaining innovative performance. Secondly, there is a number of ways to organize the interface, and there is no one best way. Third, instead of studying the Marketing - R&D interface, it is better to study the Marketing - Development and Marketing - Research interface separately. In the future, a survey will be used to generalize these and other findings, and to examine the relationship between different aspects of integration between Marketing and R&D and innovation success more in-depth. An experiment with a computer simulation game will be used to study the interface between marketing and R&D at the individual level.